Motor



Dec. 2s, 192e. H. H. MERCER noma Filed Feb. 25, 1919 2 sheets-sheet 1 ill. MIJ.

. AL N ITI/v 1,612,719 H. H MERcER I MOTOR Filed Feb. 25. 1919 2 shuts-sheer g Dec.

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Patented Bec. 28, 1926.

NETE@ .STATES islam HENRY H. MERCER,

F CLAREMONT, NEW HAMPS'HRE, ASSIGNOR TO SULLVAN MACHINERY COMPANY, A conronii'rioiv or MASSACHUSETTS.

MOTOR.

Application led February 25, 191.9. 'Serial No. 279,151.

Hy invention relates to moto-rs, and more especially to pressure fluid operated motors.

it has for its object to provide an improved motor, and more especially one having increased efficiency and power. Another object of the present invention is to provide an improved `motor which will occupy a minimum space and be free from external projecting parts. A still further object ofA the present invention is to vprovide an improved motor whose parts may be very easily assembled or disassembled. These and other objects and advantages of my invention will, however, hereinafter more fully appear.

ln the accompanying drawings I have shown one embodiment which my invent-ion may assume in practice, although it is to be understood that the same is used for illustrative pur'poses only and that the invention is not limited to lthe embodiment shown therein.

In these drawings,-

Fig. 1 is a longitudinal sectional view of my improved motor.

2 is a longitudinal sectional view of the piston used therein, taken on line -2-2 of Fig. 1.

3 is a side elevation of one of the cylinder heads.

' i is a side elevation, partly in secf one of the cylinder linings.

5 is a view taken on line 5-5 of 4 Fig. y

Wig. 6 is a side elevation of a plug.

IFig. 7 is a plan view of another cylinder head.

TEig. 8 is a side elevation of the saine haead.

9 is a section through a modified form of piston, the section being taken on a line corresponding to line 9-9 in Fig. 2.

Figs. l() and 11 are central longitudinal sections respectively showing the piston nea'r ie forwarr and near the rearward ends of i strokes.

ln this illustrative construction I have shown, for purposes of illustration, my improved motor adapted for use in a ground hog drill, in which a casing 1 of the pneumatic motor is a continuation of the drill rod of the ground hog drill, and is preferably attached to the drill rod (not shown) by a coupling 2. As is common in this type of motor, l provide the lower end of the casing 1 with internal threads or other means ti it for retaining a tool chuck (not shown). Shoulders t and 5 formed on the inner ends of the coupling 2 and chuck retainer 3, respectively, define the outer vlimits of the pneumatic cylinders and provide stopping means against which the cylinder parts may rest during the operation of the tool.

1n my preferred form, l preferably insert within the casing 1 a series of cylinder linings 6, 7, and 8, separated by 'intermediate cylinder heads 9 and 10, so that when the parts are assembled, as shown in Fig. 1, the motorconsists of three separate and distinct cylinders. The lower or forward 4cylinder 8 is provided with a cylinder head 11, and

the rear cylinder v6 is provided with a cylinder head or retaining disk 12. In the form of my invention as shown herein, the disk 12 is preferably only a retaining disk for retaining the parts in assembled position (Fig. l), this disk being held against the cylinder G by a spring 13 which abutsagainst the disk and a shoulder 14 formed in the coupling 2 around a central opening 15 in the coupling. The vparts above described may easily be assembled when the casing 1 is free from the coupling l2 by 'merely dropping the elements of the cylinders in their .proper order into the casing 1 and applying the coupling spring and disk, as shown, dowel pins, as shown at 16, being preferably used to retain the lower members in predetermined relative positions.

Any form of cylinder may be used, but in my preferred formv l preferably make the cylinder 6 'of a dierent construction from the cylinders 7 and 8, the cylinder 6 lbeing provided, at a point adjacent the rear end thereof, with a shallow recess 17 to prevent the wearing of a shoulder on the cylinder lining 6 during the operation of the motor. Near the forward end of this cylinder 6 l provide a deeper and longer recess or bypass 18 which is preferably spaced slightly from the adjacent cylinder head 9 to provide a cushioning space 19.

rlhe upper cylinder' head proper, 9, which separates the cylinders 6 and 7, is preferably provided with a central recess 2O which connects with an exhaust po'rt 21, the latter leading into la longitudinally extending groove 22 cnt in the outer'fface of the cylinder head 9, as is clearly shown in Figs. 1 and 3.

The intermediate cylinderlini-ng 7 and the Cil lower cylinder lining 8 are preferably made identical, though this is not essential to the operation of the motor. Each of these cylinder linings carries adjacent its upper end a plurality, herein six, of short, relatively shallow, longitudinally extending recesses or bypasses 23, the space 24 between these recesses and the lower face of the cylinder head 9 forming an air cushion for one of the plurality of pistons. Near the lower or forward end of each of these cylinder linings 7 and 8, is another series of recesses or bypasses 25, preferably formed in longitudinal alinement with the recesses 23, and preferably slightly longer, these recesses, as shown, being spaced from the adjacent cylinder heads l and 1l, respectively, a greater distance than the upper recesses are spaced from the cylinder heads 9 and 10 to form larger cushioning` spaces 26. The exhaust passages preferably consist ot a plurality of passageways equal in number to the recesses 23 or 25, cut in staggered or alternate relation to these recesses, and preferably on the outside of the cylinder linings 7 and 8. By this means, the same tube or lining is made to contain the bypasses 23 and 25 and the exhaust passages 27, in such a manner that a minimum quantity of material is used in the liner and the liner is made to occupy a minimum of space, there being no external projections. As is obvious, the exhaust passages may be formed in the inner wall of the casing or partially in this wall and partially in the outer wall of the lining.

The cylinder head l() which separates the lining 7 and 8, is almost identical with the cylinder head 9, having a central annular recess 28 formed therein and a port 29 connecting this recess with a longitudinally extending exhaust passage 30, the exhaust passage 30, however, extending the depth of the cylinder head lO instead of only partially the depth, as in the case of the cylinder head 9. rlhese exhaust ports 29 and 2l in the cylinder heads l0 and 9, respectively, are preferably of the saine number, herein six, as the exhaust passages 27, and the exhaust passages 30 and 32 in these heads., respectively, are preferably also of the same number as the exhaust passages in the outer face of the cylinder lining and made therewith so that the exhaust may ow from the cylinders ends through the recesses 28 and 2O through a plurality of ports to a plurality of exhaust passages, thereby making it possible to use shallower and smaller exhaust passages, and hence a much thinner and more compact Cylinder construction.

The lo-wer cylinder head l1 which abuts against the retaining shoulder 5 formed on the chuck coupling 3, preferably has no central annular recess, as have the cylinder heads 9 and l1, the exhaust from the forward end of the lower cylinder preferably passing to the tool through a central opening 3l formed in the cylinder head when the striking point is clear of this opening. A plurality of longitudinal grooves 32 extend partly through the outer surface of this cylinder head, mate with the plurality of exhaust passages 27 and connect with diagonal exhaust passages 33 so that the exhaust from the upper two cylinders and the rear end of the lower cylinder is conducted directly to the steel.

l/Vithin the cylinders I employ a single piston 34 comprising a series of interconnected spaced piston heads 35, 36, and 37. ln my preferred form shown, a central, axially disposed fluid pressure passage 38 is formd longitudinally in the piston 34 to conduct pressure fluid to the ends of the different cylinders, this axial passage 38 preferably terminating in a restricted passage 39 extending from near the center of the front piston rod 37 through the striking end of the piston to conduct live pressure fluid to the drill steel.

rlhe upper piston preferably has two pressure surfaces 40 and 4l, the upper surface 40 being, in my preferred form, always subjected to uid pressure, the lower surface 4l being only subjected to fluid pressure duru ing the cushioning action in the recess 19 or on the up stroke. ln this piston head, a plurality of passageways or ports 42 connect the fluid passage 33 with an annular recess 43, altl'iough, if desired, these passageways 42 may conduct the fluid to separate and distinct grooves similar to the grooves23 and 25, formed in the outer surface of the piston head 35 in place of the recess 43 (see Fig. 9).

The piston heads 36 and 37 are of identical construction except for the small fluid passageway 39, these piston rods having upper and lower pressure areas 45 and 46, respectively, and radial ports 47 terminating preferably in annular recesses 48.

These piston heads 35. 36, and 37 are preferably held in spaced relation by piston rods 49 and 50, preferably formed, as shown herein, integral with the different heads 35, 36, and 37. Each of these sections 49 and 50 is provided at a point near the forward end thereof with relatively shallow annular recesses 5l, 52, which govern the flow of exhaust fluid from the different cylinders.

lf it is not des "bbl to permit live pressure 'Huid to pass iroui the central passageway 38 in the piston 3iY to the 54, a plug` such :is is shown at 53 (Figs. 2 and 6) may be dropped into the piston shown in Fig'. 2. The upper surface of this plug 53 is preferably made relatively large so that the fiu'id pressure used for operating the tool will hold this plug securely in place during the cutting' operation. lf it is necessary, however. to supply an extra quantity of pressure fluid to the tvo-.ol to blow the cutin the position y lll() (l il apparent, it being clear that duri Vthe pist-on head e0.

ders, when the plug 53 will tall out. As it has been found costly to bore a small hole 39 ot the length desired, this hole may be made larger than necessary and the plug 53 may be bored as shown at 5B. lt desired,

a series ot plugs having holes ot different sizes may be used interchangeably.

From the iforegoing, it is thought that the operation oit my pneumatic hae'imer will be ng rthe douuiward or forward stroke ot rthe piston `live air is supplied through the aperture l5 to the upper surface l0 of the upper piston head 3,5 and to the upper sur-laces ll-Z) oithe piston heads and 37 ir ni the passageway 38 through the ports fr?, recesso 18, and bypasses @n the downward stroke, live liuid pressure acts on the upper surface et all the piston heads, thereby transmitting to the tool the added working powers of the dili'erent cylinders. the rearward stroke, the pressure on the upper surface 4:0 is not relieved, but the pressure on the upper surfaces or' the pistons 38 and 37 is relieved by the exhausting ot the pressure fluid from the upper part of the cylinder s l and 8 by way ofthe recesses 51,52, rezewe 12() and 28, ports @l and 29, 4to the longx `idinally etai-Lendii'ig exhaust passages iornied in the outer surfaces ot :the cylinder linings and piston heads. rlChe pressure 'fluid t igen the lower surfaces i6 ot :the pistons 236 and El? to return the piston lflzto its upper position, is admitted tothe 'lower end the cylinder linings Z and 8 lby means ot ort recesses 4S, and relatively long is the forward stroke 'of ithe piston is accompanied with a greater accumulative pressure on the dilerent 'piston heads than the rearward stroke, ythe air cushions i9 and f termed in the forward rends ot the dillerent cylinder linings are it the bypasses are of the saine th and depth the bypasses 23, the Vd movement ot the piston under sure or the live 'fluid acting on the i races -l-O and #lo ot the three piston heads f riuch more rapid than the upward nent ot the piston 34: under the action oli the 'live pressure :ic-tire," against the surtaces of the pistons 35 a .d 3i' against the live pressure acting on the large surface ot' lt will of course be noted 'that the surface el oi? piston head 35 is likewise vsubject to live pi ssure through passage a2, groove 48, and bypass 18, during a portion of the return stroke and that the torce due to this pressure likewise contributes to the overcoming of the pressure acting on the surface rlhe pressure fluid is exhausted from the lower side ot the pistons 35 and 36 by'ineans ot the recesses 5l and 52 which, in a predetermined position of the piston rod 3l in the casing l, connect the lower end of the liners 6 and 7, respectively, with the 'exhaust recesses 2O and 28 in the cylinder heads and l0, respectively. lt will be noted that because the recesses 5l and 52 are placed nearer the heads 36 and 3T, respectively, than the heads 35 and 3G, respectively, the exhaust period for the lower ends ot the cylinder linings (S and l is much shorter than the efhaust period for the upper ends of the cylinder liners i' yand 8, and that theretore agreater quantity of air is lett in the forward end of these cylinders to produce a greater cushioning'action. As stated above, the forward end et the iront cylinder liner 8 is exhausted'directly into the chuck housing l when the striking end ot the piston has been suiiiciently retracted to clear the opening .31.

lt should be noted that by the new and impro-ved construction shown herein the entire pneumatic motor may be mounted in the drilling tool ot a ground hog drill without changing the size of the casing thereof, it only being necessary to provide a proper coupling 2 and a proper chuck housing 9 'threaded 4connection between the casing l and the coupling 2, and `by reversing or turning the Vpneumatic motor upside down, when lthe parts will slide out; and that the parts may be assembled by inserting them in order, as shown in Fig. 1, into the casing l, the cylinder heads 9 and l0 being preferably split into two or more parts to facilitate the placing o'l' these heads around the repective piston rod sections t9 and 5f). lt should also be noted that the motor shown herein is et t-he valveless type, that there are no projecting parts, and, it should further be noted, that by the use et duplicate piston heads Sli-and 37 and duplicate cylinder liners 7 and 8, the power of the motor may easily be increased by merely adding lmore of these duplicate parts, thereby Agetting a heavier piston and added pressure areas. These and other advantages of my improved construction will, however, be clearly apparent to those skilled in the art.

While I have in this application specifically described one embodiment which my invention may assume in practice, it is to be understood that the same is used for illustrative purposes merely and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

lVhat I claim as new and desire to secure by Letters Patent is:

1. In a multiple cylinder motor, a cylinder construction comprising a casing member, a plurality of liner members therein, a plurality of heads separating the interior ef said cylinder into a plurality of separate piston chambers, said heads comprising a plurality of sectors cooperating to form a unit, and a piston having alternately reduced and enlarged integral portions, said enlarged portions forming piston heads disposed in said chambers while said sectors surround said reduced portions.

2. In a motor, a cylinder comprising a casing, a cylinder' liner for said casing, live fluid distribution passageways for the motor in the interior of said liner and exhaust fluid distribution passageways for the motor between the liner and the casing, a piston head within said liner having a portion of reduced diameter secured to said head, means carried by said piston head for controlling only the fluid fiow to one of said sets of passageways, and means carried by said reduced portion for controlling only the fluid fiow to the'other of said sets of passageways.

3. In a motor, a cylinder, live fluid and exhaust distribution passages for the motor formed therein, a piston in said cylinder comprising a piston head and a reduced portion projecting therefrom, a passage of reduced area located ad'acent one end of said cylinder through w lich said reduced portion passes, means carried by said piston head for controlling only the flow of fluid to said live fluid distribution passages, and means carried by said reduced portion for controlling only the exhaust of fluid to said exhaust passages.

l. In a valveless motor, a cylinder comprising a plurality of pressure chambers of equal diameters, a piston having a plurality of heads arranged in said chambers, one of said heads presenting its entire cross sectional area to fluid pressure, means for subjecting said area to continuous live pressure, and means controlled by said piston to supply fluid pressure to other surfaces of said piston heads to overcome the pressure on said circular area.

5. In a valvelessmotor, a cylinder cemprsing a plurality of pressure chambers of equal diameters, a piston member having a head reciprocable in each of said chambers, means for subjecting one of said heads continuously to live pressure over an area substantially equal to the transverse area of one of said chambers, and means controlled by said piston for admitting live fiuid periodically to a plurality of said heads to overcome said pressure acting on the area first mentioned.

6. In a percussive tool, a cylinder comprising a plurality of pressure chambers, a piston having two surfaces for driving it in one direction and two surfaces for driving it in the opposite direction, means for admitting fluid to the cylinder to exert a constant pressure on one of the first named surfaces during all movements of said piston passages controlled by the piston for admitting and exhausting pressure in one of said chambers to exert an intermittent pressure on the second of said rst mentioned surfaces, and means for exerting intermittent pressures on the second mentioned pair of surfaces comprising passages controlled by the piston and ports formed in the walls of said cylinder.

7. In a percussive motor, a cylinder, a hammer piston reciprocable therein having a hollow portion at one end, means for censtantly supplying live pressure to the end of said cylinder adjacent said hollow end and into said hollow portion, and means for distributing live pressure through the hollow portion in said piston to effect movement in both directions of reciprocat-ion of said piston.

8. In a percussive motor, a cylinder having a plurality of alined fluid pressure chambers formed therein, a hollow hammer piston having a chamber formed therein and having a plurality of heads located in said chambers, means for constantly supplying live fiuid pressure from one end of said piston during all movements of the latter and to the chamber therein, and means for supplying iiuid pressure through the chamber in said piston and to said cylinder to overcome or to be accumulative with the continuous pressure on said first mentioned end y of the piston.

9. In a motor, a cylinder having a plurality of fluid pressure chambers formed therein, a piston having a plurality of heads reciprocable in. said chambers, said piston having` an end provided with a recess, means for continuously supplying pressure to said end and to said recess, and cooperating passages formed in said cylinder and in said piston and controlled by the latter for the supply of fluid from said recess to said chambers and some of said cooperating passages permitting its exhaust therefrom.

10. In a valveless motor, a cylinder construction comprising a casing, a plurality of detachable cylinder linings therein, a plurality of detachable cylinder heads, a piston element in said cylinders, a. plurality of said linings being similar and adapted to support a head between adjacent linings, said adjacent linings and head supported therebetween having continuously cooperating passages allowing automatic reciprocation of said piston, and means for holding said linings and heads in said' casing.

11. In a motor, a plurality of longitudinally arranged cylinders, a plurality of piston heads reciprocable therein, and means for continuously admitting fluid pressure to one face of one piston head during all' movements of the latter and remaining faces ofI said piston heads to continuously reciprocate said pistons.

12. In a motor, a plurality of cylinders, a plurality of piston heads of uniform diameter reciprocable therein, mitting fluid pressure the faces of said piston heads during all movements of the latter and intermittently to the remaining faces to` continuously re'- ciprocate said pistons.

13. In a valveless percussive motor, a plurality'of cylinders, heads therefor' adapted to be disposed therebetween, al plurality of double acting pist-ons in= said. cylinders, cooperating means carried the cylinder walls'for controlling the flow of live pressure fluid, and means carried by said pistons and cooperating with a cylinder head between adjacent' cylinders adapted to control exhaust pressure fluid alternately from said adjacent cylinders.

1li. In al motor, a cylinder comprising. ak plurality of fluid pressure chambers, a piston having a plurality of heads reciprocable in said chambers and a plurality of intermediate portions of reducedldiameter, means formed in the walls of said cylinder and in said piston heads live fluid formed in said intermediate portions of said piston for the control of the exhaust from said chambers.

15. In a motor, plurality of fluid rated by annular a cylinder comprising a pressure chambers s sepahead members, a piston having a plurality of heads' reciprocable in said chambers and between vsaid head members, intermediate portions passing through said annular head members, means formed in said piston heads and in the walls of. said chambers for the distribution of fluid to the latter, and means formedin said intermediate portions and in said head members for the exhaust of` fluid from saidchambers.

16. In a. motor, a cylinder comprisinga plurality of fluid pressure chambers,.aY piston having a plurality'of heads reciprocable in said chambers, a recess in said? piston, means for supplying fluid pressure thereto,

intermittently to the and means for ad-v constantly to part of by said pistons landI forA the distribution. ofI to said chambers, and means means-for exhaustingfluid from said chambers, and means formed in the wallsfof said; chambersrand in saidv piston heads for the distribution of fluid from said'recess to'saidy chambers.

17. In a motor, a cylinder comprisingy aA plurality of fluid pressure chambers, apis-- ton having a-plurality of heads reciprocable in said chambers, a recess extending longitudinally of said piston', means forsupplying fluid pressure to said recess, means for exhausting fluid pressure from saidI chambers, meansl formed in the walls of said chambers and in' said piston heads for' the distribution of fluid from said recess tosaid chambers, and means for discharging fluid from said recess to the exhaust mea-ns for said chambers.

18. In a percussive motor, a cylinder/comprising a pair of alined fluid pressure chambers, a.common-cylinder'head separating the same, a hammer piston having a pair of heads reciprocable in saidichambersandconnected by a reducedl portion; extending' through said common cylinder head, means for supplying live fluid to said'l cylinders'` to act on the adjacent faces of two adjacent pistonl heads to actuate thepiston, and means formed in said cylinder head and' in said reduced portion.cooperating-to effect al'- ternate exhaust from. the adjacent ends of said chambersv to substantially' atmospheric pressure'.

19. In a permissive-motor', a cylinder comprising a' plurality of'alinedy' fluid pressure chambers, a hammer piston having a plurality. of heads freely reciprocable inl said chambers'and connectedby reducedlportion's, motive fluid supply means comprising means carriedy by certain of saidv heads# for admititing live fluid pressure` alternately. to each end ofy their-respective cylinders toiactuate said piston in'opposite directions, andr means formed on said reducedl portions for alternately exhaustingr adjacent ends of adjacent cylinders.

20.- A motor comprising ai plurality of cylinders, a plurality of'pistons freelyy reciprocable insaid-cylind'ers, means for continu'- ously supplying fluid pressure to one end of one of said pistons during all movements thereof, and means for supplying fluid pres.- sure from said end to the remainder' of said pistons to overcome said continuousv pressure on said lirst piston.x

21. A motor comprising a plurality of cylinders, a plurality. of pistons of vsubstantially the same diameter freely reciprocable in said cylinders, means for; continuously supplyingy fluid. pressure; to oneI end' of one of vsaid pistons during: all movements thereof, andr means for supplying fluidpressure from said end to the remainder of saidpis'- tons toovercomeA said continuous pressure on said first pistonin one direction of movement or be accumulative therewith in the other direction of movement.

22. In a drilling mechanism, a motor cylinder, means for supporting a hollow drill steel therein, a reciprocable piston therein having a bore extending throughout its length and of .different diameter at different points, motor distribution passages communicating with said bore, and removable means disposed within said bore for controlling the flow yof fluid through the same to said steel.

23. In a multiple cylinder percussive motor, a cylinder comprising a casing having a bore, cylinder liners and heads in said bore forming separate chambers, live fiuid distribution passages for the motor on the interior of said liners, exhaust fluid passages for the motor between the liners and heads and the casing, piston heads in said chambers having portions ofl reduced diameter secured to said heads, means carried by said piston heads for controlling the flow of fluid to one of said sets of passages, and means carried by said reduced portions for controlling the flow of fluid to the other of said sets of passages.

24. In a multiple cylinder percussive motor, a cylinder comprising a casing having a bore, cylinder liners and heads in said bore forming separate chambers, live fluid distribution passages for the motor on the interior of said liners, exhaust fluid passages for the motor between the liners and heads and the casing, piston heads in said chambers having portions of reduced diameter secured to said heads, means carried by said piston heads for controlling the live uid distribution passages, and means carried by said reduced portions for controlling said exhaust fluid distribution passages.

25. In a multiple cylinder percussive motor, a cylinder comprising a casing having a bore, a plurality of cylinder liners in said bore, live Huid distribution passages for the motor formed in the interior of each of said liners, exhaust fluid passages for the motor formed between said liners and said casing, piston heads within said liners having portions of reduced diameter secured to said heads, means carried by said piston heads for controlling the flow of Huid to one of said sets of passages, and means carried by said reduced portions for controlling the (low of fluid to the other of said sets of passages.

26. In a multiple cylinder percussive motor, a cylinder comprising a casing having a bore, a plurality of cylinder liners in said bore, live fluid distribution passages for the motor formed in the interior of each of said liners, exhaust Huid passages for the motor formed between said liners and said casing, piston heads within said liners having portions of reduced diameter secured to said heads, means carried by said piston heads for controlling said live Huid distribution passages, and means carried by said reduced portions for controlling said exhaust fiuid distribution passages.

2T. In a multiple cylinder percussive valveless motor, a cylinder construction comprising a casing member having impertorate side walls and a bore substantially throughout its length having a reduced portion at one end thereof, a. plurality of sleevelike liner members insertable in said bore, a plurality of head members between said liner members separating the interior of the cylinder in a plurality of separate chambers, said head members comprising a plurality of cooperating sectors, and a hammer piston having` alternately reduced and enlarged integral portions, said enlarged portions torming piston heads disposed in said chambers while said sectors surround said reduced portions.

28. In a motor, a cylinder construction comprising a casing member having a bore substantially throughout its length, a plurality of cylinder liners insertable in said bore, a plurality of head members insertable in said bore, a closure member secured at one end of said bore, and means for resiliently maintaining said liners and head members in operative assembled relation comprising a spring engaging said closure member.

29. In a multiple cylinder valve-less percussive motor, a cylinder comprising a casing member having a bor-e, a plurality of cylinder liners in 'said bore, ay plurality of head members between said liners separating the interior of the cylinder into a plurality of separate chambers, a hammer piston having ,heads disposed in said chambers, and means tor distributing live and exhaust fluid in said motor comprising a constant pressure chamber in said piston and passages formed in said piston, liners, and head members.

30. In a multiple cylinder valveless percussive motor, a cylinder comprising a casing member having a bore, a plurality of cylinder liners in said bore, ay plurality ot head members between 4said lin-ers separating the interior of the cylinder into a plurality of separate chambers, a hammer piston having heads disposed in said chambers, and means for distributing motive fluid in said motor comprising axially extending inlet and exhaust passage means, a. constant pressure chamber in said piston and passages formed in said liners and head members.

3l. In a. percussive motor, a cylinder having enlarged and reduced bores, live fluid and exhaust fluid distribution passages for the motor formed in said cylinder, and a hammer piston in said cylinder having a grooved piston head in the enlarged bore and a reduced portion in the reduced bore,

the grooved piston head controlling only the live Huid distribution passages while the reduced portion controls only the exhaust fluid distribution passages.

32. In a percussive motor, a cylinder, a hammer piston reciprocalole therein having spaced heads and a hollow portion throughout a portion of its length, means for constantly supply/fing live fluid to the end of said cylinden adjacent the hollow end and into 10 effect movement in both directions of recipro- 15 cation of said piston.

In testimony whereofI affix mv signature.

HENRY H. MERCER. 

